Obama said it was important for officers to know the community they were protecting and to undergo training to avoid "implicit biases". "That means you", Obama said. "This is not just stuff I make up".
Because this is a big country, he added: "I think it is fair to say we will see more tension between police and communities this month, next month, next year, for quite some time".
So far, Obama's Black Lives Movement has proved a roaring political success for Obama because it has increased African-Americans' focus on the pending 2016 election.
Obama bristled at the suggestion.
Obama told Patrick he has been "unequivocal" in his support for police.
"I have also insisted throughout all these processes that law enforcement is deserving of due process just like everybody else", he said.
"So I appreciate the sentiment". I think the difference is when there's a limited part of the pie, we're sort of pitted against each other to get those things and I think those things spill out into issues that become police issues. I'm here to say we must reject such despair.
The good news, Obama said, is people are talking about the problems.
The special titled The President and The People: A National Conversation will air live from Washington, D.C. World News Tonight anchor David Muir will co-moderate the event with ESPN commentator and host of ESPN2's His & Hers, Jemele Hill.
The White House released Obama's statement a few hours after a truck drove onto the sidewalk and plowed through a crowd of revelers who'd gathered to watch fireworks late Thursday. "That's what I have to do?"
Several participants spoke of a breakthrough moment, saying every single person had a chance to speak, and people felt like they were truly being heard by those normally on the opposite side of the divisive issue of race and law enforcement.
Mr Cunningham said the Dallas Police Department exemplified that commitment to its community when officers used themselves as human shields to protect bystanders from possibly being shot.
The city medical examiner found the apparent police chokehold contributed to Garner's death, but a grand jury declined to indict the officer in the death.
On Twitter, Garner called the event a "farce" and a "sham". "I ask for your help", was the plea from the son of Alton Sterling, who was killed in Baton Rouge. "And some of it involves us being very conscious of our assumptions because white folks and Latino folks also carry some assumptions", he said. Reynolds, who livestreamed what followed his shooting on Facebook, said she was scared for her daughter's future and asked the president remotely, "What do we do?"
On Thursday evening, Patrick appeared less than satisfied with Obama's answer to his initial question, which included an unaddressed request to put blue lights on the White House as a way of expressing solidarity with law enforcement.